My perfectly healthy kid, sitting on the exam table in his soccer jersey, was dumbstruck. So was my wife.

Our doctor’s warning — one he now gives to all his young patients and their families — came from his years of caring for an increasing flow of kids suffering serious, sometimes life-altering concussions from playing soccer. “If I don’t get this information across,” he told me, “even at the risk of upsetting people, I’ve failed. I haven’t done my job.”

According to Dr. Robert Cantu, one of the country’s top specialists in youth sports injury, soccer is right up there behind football in the incidence of reported concussions in kids. The Centers for Disease Control estimates that about 10,000 kids land in the emergency room every year for soccer-related brain injuries.

But at the same time, following the doctor’s orders seemed unthinkable.

My wife and I have raised three soccer-mad kids in a soccer-mad New Jersey town in an increasingly soccer-mad nation. From fall through spring, our evenings and weekends are consumed by practices and games; our home decorated with the requisite smelly pile of cleats, shin guards and bits of astroturf. And then comes all the laundry…

We know the benefits of team sports are huge and long-lasting, and when our kids were little, we thought we were doing the right thing by steering them away from football, especially after a tragedy in 2008 when a 16-year-old from our local high school died from a concussion and brain hemorrhage he got on the field. Soccer seemed like the “safe” alternative.

“Soccer’s a contact sport. Kids can get hurt. I’m not looking to bubble-wrap my kids, but I’d be lying if I said my wife and I weren’t increasingly uneasy while watching from the sidelines.”

But as our kids got older and bigger and their play became more intense, our pediatrician’s warning kept creeping back into our minds. My wife saw two girls collide over a header; one of them left the field in an ambulance. A teammate of my son’s fell hard after going up for a header. The headaches and dizziness from his concussion lasted months, took a toll on his schoolwork and has kept him from playing soccer ever since. Of the 17 boys on Jack’s current team, at least three have had concussions within the last year.

Believe me, I get it: soccer’s a contact sport. Kids can get hurt. I’m not looking to bubble-wrap my kids, but I’d be lying if I said my wife and I weren’t increasingly uneasy while watching from the sidelines.

During the World Cup last year, we cheered along like everyone else, but also winced when players like Germany’s Christoph Kramer took brutal blows to the head but were allowed to keep right on playing. Kramer was apparently so disoriented that when the final whistle blew, he had to check with a referee whether the game was over or not. What kind of lesson was that teaching my kids?

That’s when I read about a fledgling movement led by Brandi Chastain and other former members of the United States women’s World Cup team who were trying to remove heading for kids aged 14 and under. (Heading, of course, is the deliberate striking of an airborne ball with your head.) Though brain injuries can also be caused by falls or collisions with other players, leaping up for a header can often cause those accidents.

Just a few years ago Chastain had defended heading in kids soccer, but she explained to me why she’d changed her mind. She was now the parent of an 8-year-old soccer player. She’d also heard from her World Cup teammates, several of whom have lingering symptoms from concussions they had suffered on the pitch. But most of all, Chastain said the emerging science about head injury and concussions had convinced her this was the right move, and one that wouldn’t fundamentally alter the game she loves.

She said young players can still practice heading, but just use a softer ball instead. She’d rather see kids re-double their focus on foot-skills and then, when they’re 14, she says heading can be safely introduced into their game. Dr. Cantu, who’s a partner on Chastain’s campaign, said there’s some evidence that heading the ball a lot — around 1,000 times a year — can cause brain injury, even if those headers aren’t causing noticeable concussions. In addition, he said kids’ brains are still developing, so any blows to the head can damage crucial nerve fibers before they’re fully formed. Finally, kids experience what Cantu calls “the bobble-head effect”: their heads are disproportionately large compared to their bodies, and their relatively weaker neck muscles can’t protect their heads as much as full-grown adult’s can.

For those reasons, even though he admits conclusive evidence of harm is still lacking, he thinks eliminating heading from kids’ soccer is the prudent way to go.

Very few soccer programs have taken this advice. Cantu and Chastain say change needs to come from the top, from governing bodies like FIFA or the U.S. Soccer Federation. Those organizations wouldn’t comment to me on any plans they might have, in part because they’re currently being sued by a group of soccer-parents who allege they’ve not done enough to prevent head-injuries for kids.

So what’s a soccer parent to do? My wife and I haven’t seriously considered telling our kids they can’t play anymore, because we think the benefits still outweigh the risks. But we have told them to avoid heading the ball until they’re 14. To Jack, this is a sacrilege, but he says he’ll comply. Chastain believes if enough parents speak up about their concerns, things might change, but heading is still part of her own 8-year-old son’s league.

So next season, we’ll be out at the games, watching our kids succeed and fail, their faces red with exertion. Frankly, it is one of the joys of our lives. My wife and I can talk our kids’ ears off about the value of hard work and dedication, but we don’t have to say a word when they’re out there with their teammates, absorbing those same crucial lessons on the field.